Coated core



Patented llov. A5, 1929 UNITED STATES vParri-:N11 ori-Ica `HOWARD GEORGEWALKER, OF BERWYN, ILLINOIS, ASSIGNOR TO WESTERN ELECTRIC COMPANY,INCORPORATED, QF NEW YORK, N. Y., ACORPORATION OF NEW YORK COATED COREApplication med June 5,

. This invention relates to improvements in coated cores, and moreparticularly to electrical conductors vcoated with an insulat ingmaterial which is impervious to moisture.

An object of theinvention is to-provide an electrical conductor. with aninsulating material havin the desirable moisture-proof qualities of rubr, and in addition one which has low dielectric losses, is flexible andsufloiciently tough and durable to resist abrasion in handling.

Another object of the invention is to provide an electrical conductorwith a coating of insulating material which is impervious 15 tomoisture, the coating being of a type that it may be rapidly applied andincluding indients which are less expensive than the mgredientspreviousl used in insulating materials having equiva ent physical,dielectric, and moisture-proofing qualities. v An article made inaccordance with the resent invention may comprise a core, preerably instrand form and, in cases where the finished article serves as anelectrical conductor, of electrical conducting metal such as co per,coated with fibrous material which may e applied in any suitable manner.Although the fibrous material may be applied as a strand serving, as abraided covering, or both,or applied 1n some other manner, Ipreferably-coat the metallic core with pulp made of some cheap materialsuch as wood, manila,

jute, esparto, or hemp, but the pulp may when desired be formed of rag,cotton, linen, asbestos, etc. This pulpous material is preferablyapplied to the core by the Ymethod and apparatus disclosed 1n PatentsNos. 1,615,416 and 1,615,417, issued on January 25, 1927 to H. G. Walkeret al., respectively, wherein the pulpous material is held on the coresolely by an intermingling of the fibers thereof. The coated coreis thenimpregnated with rubber latex which is a product of the rubber treecontaining some water, or it may '50 The impregnation maybe accomplishedby rubber latex each of the fibers of the pul ous be found preferable insome instances to dilute- 1923. serial no. 43,55?.

Vcore a plurality of times, drying the coating between each immersion inorder to cause a thorough impregnation thereof. Other methods of imregnation may be employed as by the use o vacuum or pressure in a wellknown manner. i In impregnating the pulpous material with material issaturated with the latex w ich renders the fibers to an extent elastic.The elasticqualityngiven the Iibers and the cement- -ing'action of therubber causes the pulpousf material to resist abrasion as well as i11'v7o creases the iiexibility of the coating.- A

Electrical conductors coated Withlpu-lpous material impregnated withrubber latex may be used finder conditions approximating those to whichordinary rubber covered wiret is subjected. Conductors so coated may beused to advantage'in' the manufacture of telephone switchboard cablesince the coating is moisture-pro0,`has-low dielectric losses, and istough enough to resist abrasion during the handling of the cable inapplying it to the switchboard. The simplicity of the method ofproducing and applying the insulation to an electrical conductor, aswell as the cheapness of g5 the ingredients employed, results in anelectrical conductor considerablyless expensive than conductorsheretofore provided with an insulation having similar physical, insulatA., ing, and moisture-proof characteristics. In the accompanying drawingillustrating an electrical. conductor made in accordance with theinvention, the reference numeral' indicates a strand-of conductingmateriah,V preferably of copper, which is coated with pulpous materialpreferabl applied by the method and apparatus disclosed.; in theWalker-March patents hereinbeforereferred to. The insulating material asshown in the drawing cut away to more clearlyshow the" characterthereof, and the reference numeral 10 indicates a portion of thepulpousmaterial unimpregnated, while the reference numeral 15 indicatesthe said material after it has been impregnated with rubber introducedby an emulsionv free from sulphur.

What is claimed isz 1. 'An electrical conductor comprising a metallicstrand znd la, continuous, homlilageneous, integra coating engagin t estrand, consisting of felted fibrous pulgp free of adhesive materialimpregnated with a rubber emulsion.

,2. An 4electrical conductor comprising a metallic strand and acontinuous, homogeneous', integral coating enclosing the strand,consisting solely of sel'y felted and matted paper impregnated' with arubber emulsion.

3.- An electrical conductor comprising ay metallic strand and acontinuous, homogeneous, ,interah flexible coating` enclosmg the stra'n,consisting of loosely felted fibrous paper free of adhesive vmaterialimpregnated withrubber introduced in an emulsion.

In witness whereof, I hereunto subscribe my name this 23 day of May A.D., 1923.

HOWARD GEORGE WALKER.

